7.2.2 Strictly-enforced
inclusion property with L1 data caches

The L2 memory system requires support for inclusion between the L1 data caches and the L2
cache. A line that resides in any of the L1 data caches must also reside in the L2 cache.
However, the data can differ between the two caches when the L1 cache line is in a dirty
state. If another agent, a
core
in the cluster or another cluster, accesses this line in the L2 then it knows the line is
present in the L1 of a processor and then it queries that
core
for the most recent data.

This strictly-enforced inclusion property has the following
benefits:

Any AXI or CHI ReadClean operation that results in a line being in shared state in the L1 data
caches can be returned from the L2 cache. This yields the highest performance for
delivering data to a
core.

When powering down the processor, it reduces the
time to clean and invalidate the entire L1 data cache.